[Bug c++/54319] [9/10/11/12 Regression] empty class causes error while non-empty does not

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54319

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I think the problem is here in init.c:
      /* If the type has data but no user-provided default ctor, we need to
zero
         out the object.  */
      if (type_has_non_user_provided_default_constructor (type)
          && !is_really_empty_class (type, /*ignore_vptr*/true))
        {
          tree field_size = NULL_TREE;
          if (exp != true_exp && CLASSTYPE_AS_BASE (type) != type)
            /* Don't clobber already initialized virtual bases.  */
            field_size = TYPE_SIZE (CLASSTYPE_AS_BASE (type));
          init = build_zero_init_1 (type, NULL_TREE,
/*static_storage_p=*/false,
                                    field_size);
          init = build2 (INIT_EXPR, type, exp, init);
          finish_expr_stmt (init);
        }